Bags made of plastic film such as thin polyethylene film have been used in various sizes Small bags are used in the packaging of sandwiches and the like; larger bags are used as grocery bags and even larger bags are used for containing trash. The present invention is particularly related to the medium-size grocery bags where the loading of the bag is through an open top. So-called "T-shirt" grocery bags of the type shown in the Kuklies, et al U.S. Pat. No. 4,165,832 have been extensively used for packing and carrying groceries from retail markets. These T-shirt bags are inexpensive, strong, easy to carry by their integral handles, and have been widely used successfully. The most common complaint about these bags is that when they are placed on a seat or in the trunk of a car, the loaded bags often tip over, spilling their contents.
Proposals have been made for closures for grocery bags. U.S. Pat. No. 3,774,838-Christie shows a plastic bag with a detachable tie which can be used to close the open top of the bag.
Bags used for other purposes have utilized a draw tape closure. U.S Pat. No. 4,558,463-Boyd describes a thermoplastic trash bag with a draw tape closure
The "tipping" problem would be at least partially obviated if thermoplastic grocery bags had a truly flat bottom when filled with groceries. The common T-shirt bag such as in Kuklies, et al has a partially flat bottom because of the side gussets which expand to present a flat bottom when the bag is filled Bottom-gusseted bags have also been used. U.S. Pat. No. 3,982,687-Auer discloses a bottom-gusseted bag with a top closure which includes a strap which can be detached from the bag and used to close the top of the bag.
For various reasons, the foregoing and other proposals for avoiding the grocery bag tipping and spilling problem have not been successful.
It is an object of the present invention to provide a thermoplastic bag with an integral draw tape to close the top of the bag and a bottom gusset which expands to present a flat bottom when the bag is filled with groceries.